1. Field of the Invention
The invention relates to a gemstone on which respectively at least four facets of equal size have been cut in the upper part and the lower part above and below a girdle plane, which have a parallel base edge, wherein the angle between an upper part facet and the girdle plane is less than the angle between a lower part facet and the girdle plane.
2. Prior Art
Such a cut of a gemstone is known, for example, from DE-PS 15 57 625, wherein an equal number of facets on the upper part and facets on the lower part determine the appearance and its optical properties.
A comparable cut is known from DE 42 10 995 A1, wherein it is intended that particular angles between the facets on the upper part and facets on the lower part lead to a particularly noticeable appearance, essentially by planar effects which differ in their brightness.
A further development of these types of cuts is shown in DE 32 02 302 A1, wherein outer facets include the girdle plane.
Finally, DE 27 20 267 C2 shows a diamond, which has a very complex structure of cut surfaces, among them also narrow triangular facets which, combined into groups, widen in a fan shape from the area close to the top of the diamond down to circumferential lateral facets. In its optical effects, the interplay of the multitude of different facets also leads to a complex, rather confusing appearance.